Symptoms of Rocky Mountain Spotted Fever in Dogs

Source: PetWave, Updated on July 16, 2015
Rocky Mountain Spotted Fever

How Rocky Mountain Spotted Fever Affects Dogs

Some dogs infected with the organism that causes Rocky Mountain Spotted Fever (RMSF) never become observably ill. Others, however, develop a high fever, body aches, tissue and organ swelling and a great deal of discomfort. Dogs with severe cases of this disease are extremely ill and require immediate veterinary attention. RMSF can be fatal.

Symptoms of Rocky Mountain Spotted Fever

Dogs infected with Rickettsia rickettsii may have subclinical disease, which means that they show no outward signs of illness even though they are infected with the microscopic organism. They also may develop clinical disease, which means that they do have symptoms that their owners can see. Unfortunately, the signs of RMSF can be quite nondescript and often mimic the signs of other diseases. During high tick season, dogs usually develop acute symptoms, including one or more of the following:

  • Weakness
  • Listlessness
  • Lethargy
  • Depression
  • Fever (often high; usually develops within 2 or 3 days after a prolonged tick bite)
  • Lack of appetite (inappetence; anorexia)
  • Weight loss
  • Eye redness (conjunctivitis; scleral injection)
  • Difficulty breathing (dyspnea; respiratory distress)
  • Exercise intolerance
  • Cough
  • Vomiting
  • Swollen limbs (limb edema)
  • Swollen tissues (edema of the face, lips, scrotum, prepuce, ears, other tissues)
  • Painful joints
  • Muscle pain (especially in the neck region)
  • Stiff, unstable gait (uncoordination; ataxia; balance problems)
  • Rash around the area of a tick bite (not especially common)
  • Enlarged regional lymph nodes (lymphadenopathy)
  • Enlarged spleen (splenomegaly)
  • Damage to kidneys, brain, heart and/or skin
  • Nosebleeds (epistaxis; spontaneous bleeding; may be associated with sneezing)
  • Bleeding/coagulation abnormalities
  • Blood in the urine (hematuria)
  • Blood in the feces (hematochezia)
  • Digested blood in the feces (melena)
  • Behavioral changes; altered mental state
  • Stupor
  • Seizures
  • Coma
  • Abnormal heart rhythms (arrhythmias)
  • Shock
  • Sudden death

These symptoms can mimic those of canine Lyme disease, distemper or ehrlichiosis, among many other disorders.

Dogs at Increased Risk

Purebred dogs reportedly are more likely to develop symptoms of RMSF than are mixed-breed pets. German Shepherd Dogs are predisposed to this illness. The reason for this association is unclear, but it does suggest a potential genetic contribution to the cause of the disease. Dogs that are free-roaming, or that spend significant time outdoors in tick-infested areas, such as dogs used for hunting, tracking or field trial competitions, as well as dogs receiving blood transfusions, also are at increased risk.

Disorders Similar to Rocky Mountain Spotted Fever

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